The present invention concerns a reinforced concrete flat slab and the lost mold elements used in its manufacture. The reinforced concrete flat slab is a flat plate designed to span in two directions.
The present invention is directed to provide lost mold elements, preferably, of recycled plastic material, for manufacturing reinforced concrete flat slabs. They are intended for incorporation into the flat slabs and, thereby they also solve the environmental problem of the disposal of plastic material waste.
The prior art is described in EP 0 884 427, DE 30 06 672, GB 1 141 691, EP 0 057 943, U.S. Pat. No. 1,329,978, U.S. Pat. No. 1,729,612, and DE 646 941. The most relevant prior art document is document EP 0 884 427, in which is claimed a mold having a box shape, which is made of recycled plastic material. In fact all these references are quite different from solution presented by the present invention as set forth in the following discussion.
The mold elements according to the present invention are intended to create voids inside of the reinforced concrete flat slabs and, hence to lighten the flat slab, as well as to allow the molding of beams reinforced with steel rods, which are defined by the sides or lateral wall of the mold elements and which include reinforcing steel rods in their interior. The inclusion reinforcing steel rods is possible thanks to the supporting parts for the steel rods, which are connected to mold elements.
The use of voids and beams in the manufacturing of conventional reinforced concrete flat slabs has as its object providing stronger and lighter reinforced concrete flat slabs.
The casting of the reinforced concrete flat slabs, with this type of mold rises to types of problems. The first is that mold elements are prone to float in the fresh concrete, because the mold elements are hollow and the difference density between the mold elements and the fresh concrete and additionally to the bonding of the fresh concrete to the mold. The second problem is the evacuation of the air during the casting, as sometimes are created air chambers near the bottom of the mold elements, when during the casting of the flat slab vibration is applied to the concrete mass.
For solving the first problem, the mold element according to the invention has attachment means for securing the mold element, which do not allow its floatation, and grooves and substantially cylindrical hollow parts, which allows the concrete to run all around the surface involving the mold element and be better bonded to it.
For solving the second type of problem, according to the invention openings and gaps are arranged for air evacuation, which allow the air circulation through the mold element and hence its easier evacuation.
Accordingly, the present invention provides a reinforced concrete flat slab comprising lost mold elements, which are intended, when used together with other mold elements, for creating voids and allowing the casting of reinforced beams, the mold element being made of recycled plastic material and having the shape of a hollow box, substantially of a flat prismatic shape, characterized in that the lost mold element is formed from two half boxes, an upper one and a lower one, removably joined together, each mold element having sides or lateral walls, with profiles, which define together with other sides or lateral walls of other mold elements, xe2x80x9cIxe2x80x9d shaped profiled channels for casting beams, whereby between the sides or lateral walls are arranged steel rod attachments and distribution supports for securing the steel rods, for reinforcement of said xe2x80x9cIxe2x80x9d shaped beams.
According to a first variant of the present invention the said lost mold element has a base arrangement, the lower main face being in the bottom of the said lower half box, spaced apart of said base arrangement, at least said lower main face of said lower half box having grooves, the lateral walls and said base arrangement of said mold element having skew notches, for the different steel rod attachment and distribution supports, for securing the steel rods, the protuberances or nails being secured in said lower face of said lower half box, there being substantially cylindrical hollow connecting parts in the internal faces of said half boxes, which provide to the mold element with a good compression and deformation resistance, said base arrangement being secured to the lower half box by means of skew notches, which allow the existence of a pre-set gap for the air circulation, there being also small openings in said upper half box, covered with a very thin plastic film, which allow, whenever such is necessary, air circulation.
Each mold element has sides or lateral walls with the profiles, which define together with others sides or lateral walls of the others mold elements, xe2x80x9cIxe2x80x9d shaped profiled channels for casting means.
The mold element for beams according with the present invention presents spacer feet in the lower face of lower half box.
The junction between the two half boxes of the mold element is removable and includes skew notches.
According to the present invention the mold element has such dimensions and geometry to allow the easier control of all dimensions requested by the flat slabs in which they are going to be included.
The mold element has grooves, which allow for better flowing and bonding of the fresh concrete in the areas more strangled, this is, the lower portion of the mold element.
According to a second variant of the present invention, the sides or lateral walls of the said mold element have a corrugated configuration, for providing a greater resistance to them, and the main upper and lower faces presenting skew notches and the lateral walls of said mold element presenting holes for nesting the steel rod attachment and distribution supports. The corrugated configuration consists of ridges, said ridges being triangular shaped, and arranged in such a way that the bases of the triangles are disposed close to the separation plan of said two half boxes. The main faces have at least two grooves parallel one another and parallel to an edge of the main face of the mold element and several spacer feet, perpendicular to said faces, arranged evenly upon the its surface, each one having at least one flange with a recess for receiving a steel rod. The internal faces of said half boxes have substantially cylindrical connection hollow parts, which provide to the mold element a good compression and deformation strength, there being further small openings in said mold element, which allow, whenever such is necessary, air circulation.
Each mold element has sides or lateral walls with profiles, which define together with others sides or lateral walls of the others mold elements, xe2x80x9cIxe2x80x9d shaped profiled channels for casing beams, the spacing between each one of said mold elements being determined by the steel rod attachment and distribution supports.
The junction between the two half boxes of the mold element is removable.
According to the present invention thr mould element has such dimensions and geometry to allow the easier control of all dimensions requested by the flat slabs in which they are going to be included.
The mold element has grooves, which allow for better flowing and bonding of the concrete in the areas more strangled, this is, the lower portion of the mold element.